DE 10 2008 032 544 A1 describes setting braking forces at the vehicle wheels or axles as a function of brake temperature and of wheel slip values. As a result, braking force distribution takes place on the basis of the slip values, i.e., closed-loop adhesion control.
Different closed-loop control systems are known for brake systems of utility vehicles. Closed-loop slip control systems such as ABS and traction control systems serve to prevent and/or to regulate locking of the braked wheels and spinning of the driven wheels. Driving stability control systems such as ESP and rolling prevention functions serve to prevent skidding and rolling (lateral tipping over) of the vehicle. Longitudinal control systems such as cruise control (CC) functions and adaptive cruise control (ACC) systems relate to adaptation to other road users. Furthermore, brake lining wear control systems are known for bringing about the most uniform possible brake lining wear at the different wheels or axles.
In the event of a braking request by the driver or by one of the stability programs, the overall brake pressure that is determined or the overall braking force that is determined can be distributed differently between the axles of the vehicle. This brake pressure distribution or braking force distribution is carried out, in particular, in an axle-dependent fashion in order to take into account the various axle loads, since a large axle load permits greater traction and better transmission of the braking force to the roadway. This is intended to prevent, in the event of such adhesion-appropriate braking force distributions (BKV) or brake pressure distributions (DV or phi), the braked axles with relatively small axle loads from locking too quickly. A relatively large degree of brake lining wear at the axles that have a relatively large axle load is disadvantageous, and therefore, in the case of adhesion-appropriate braking force distributions or brake pressure distributions, such axles are allocated a higher braking force or brake pressure.
On the other hand, when brake lining wear control operations are carried out, frequent locking of the axle that has a relatively low axle load and is actuated with a high brake pressure can take place. For example, in buses, this axle with a tendency to lock is generally the front axle, the locking of which can be perceived as unpleasant by the driver and the passengers; in the case of empty trucks and semitrailer tractors traveling solo, this axle with a tendency to lock is generally the rear axle; driving stability is also adversely affected here.
Furthermore, measurements of ambient conditions are known, for example, from DE 10 2004 018 088 A1, DE 10 2007 060 858 A1, EP 1 635 163 A2 and DE 101 26 459 C1.